WO2017150318A1

WO2017150318A1 - Robot arm mechanism, and direct-acting extension/retraction mechanism

Info

Publication number: WO2017150318A1
Application number: PCT/JP2017/006721
Authority: WO
Inventors: 尹　祐根
Original assignee: ライフロボティクス株式会社
Priority date: 2016-02-29
Filing date: 2017-02-23
Publication date: 2017-09-08
Also published as: JP6725640B2; CN108698236A; JPWO2017150318A1; US20180372194A1; DE112017001033T5

Abstract

The purpose of the present invention is to improve the workability of exchanging rollers which form a direct-acting extension/retraction mechanism of a robot arm mechanism. A direct-acting extension/retraction mechanism provided to a robot arm mechanism is provided with first and second segments (51, 52) which are respectively coupled so as to be capable of bending. An ejection mechanism (56) is provided with: a plurality of rollers (59, 62) which firmly sandwich the first and second segments (51, 52), and support the first and second segments such that the first and second segments can move back and forth; and a drive gear (64) which meshes with linear gears of the first segments (51) to the rear of the rollers (59, 62), ejects the first segments (51) forwards, and returns the first segments (51) rearwards. The ejection mechanism is formed from separate bodies, namely a roller unit (58) provided with the rollers (59, 62), and a drive unit (63) provided with the drive gear (64). The drive unit (63) is fixed to a drum body (60) of an ascending/descending part (4). The roller unit (58) is formed so as to be capable of being attached to and detached from the drive unit (63).

Description

Robot arm mechanism and linear motion expansion / contraction mechanism

Embodiments of the present invention relate to a robot arm mechanism and a linear motion extension mechanism.

Conventionally, articulated robot arm mechanisms have been used in various fields such as industrial robots. The inventors achieved the practical application of a linear motion expansion / contraction mechanism. This linear motion expansion / contraction mechanism is a very useful structure that eliminates the need for elbow joints and realizes elimination of singularities.

The linear motion expansion / contraction mechanism has a plurality of plate-shaped pieces that are flexibly connected and a plurality of U-shaped grooves that are also flexibly connected on the bottom side, and these are joined to each other. By doing so, a columnar arm portion that is straightened and has a certain rigidity is formed. When the motor of the linear motion expansion / contraction mechanism rotates forward, the arm portion that has become a columnar body is fed out from the feeding mechanism, and when it rotates in the reverse direction, the arm portion is pulled back. Behind the feed mechanism, the joined state of the frames is released and the rigid state is restored to the bent state. The two types of pieces recovered to the bent state are bent in the same direction, and are accommodated together in the support column.

In the linear motion expansion / contraction mechanism, as an important structure together with two types of frames, there are a plurality of rollers that firmly sandwich the two types of frames. These rollers are made of, for example, a self-lubricating resin. The rollers are subjected to a load from the arm portion, the hand provided on the arm portion, and the work gripped by the hand, are most likely to be damaged, and are relatively frequently replaced. It can be said.

The purpose is to improve the workability of exchanging the rollers constituting the linear motion expansion / contraction mechanism.

In the robot arm mechanism according to the present embodiment, a support column having a rotating rotary joint is supported on a base, and a undulation having a undulating rotary joint is placed on the support, and the undulating unit is directly mounted on the undulating unit. A linear motion expansion / contraction mechanism provided with a dynamic elastic arm portion is provided. A wrist part to which an end effector can be attached is provided at the tip of the arm part. The wrist is equipped with at least one rotary joint for changing the posture of the end effector. The linear motion expansion / contraction mechanism has a plurality of first pieces having a flat plate shape and a plurality of second pieces having a groove shape having a U-shaped cross section. The first frames are connected to bendable at the front and rear ends. The plurality of second frames are connected to each other so that they can be bent at the front and rear ends of the bottom plate. The heads of the plurality of first frames and the heads of the plurality of second frames are coupled to the coupling unit. When the first and second frames are joined, they are stiffened linearly to form the arm portion, and when the first and second frames are separated from each other, they return to the bent state. The feeding mechanism includes a plurality of rollers that firmly hold the first and second frames and support them so as to be movable back and forth in order to secure the joined state of the first and second frames, and a first frame separated behind the rollers. And a drive gear that feeds the first frame forward and pulls it backward. The feed-out mechanism is composed of a separate roller unit equipped with a roller and a drive unit equipped with a drive gear. The drive unit is fixed to the rotating part of the undulating part. The roller unit is configured to be detachable from the drive unit.

FIG. 1 is an external perspective view of a robot arm mechanism according to the present embodiment. FIG. 2 is a side view of the robot arm mechanism of FIG. FIG. 3 is a view of the internal structure of the robot arm mechanism of FIG. 1 as viewed from the cross-sectional direction. FIG. 4 is a diagram showing the configuration of the robot arm mechanism of FIG. FIG. 5 is a perspective view of the arm delivery mechanism of FIG.

Hereinafter, the robot arm mechanism according to the present embodiment will be described with reference to the drawings. Here, a polar coordinate type robot arm mechanism provided with a linear motion expansion / contraction mechanism will be described as a robot arm mechanism according to the present embodiment, but other types of robot arm mechanisms may be used.

1 is a perspective view of a polar coordinate type robot arm mechanism according to the present embodiment, FIG. 2 is a side view thereof, and FIG. 3 is a side view of the robot arm mechanism with a side cover removed. FIG. 4 shows the configuration of the robot arm mechanism in graphical symbols. The base 1 of the robot arm mechanism is typically provided with a column portion 2 that forms a cylindrical body vertically. The strut portion 2 accommodates a first joint portion J1 as a turning and rotating joint portion. The first joint portion J1 includes a torsional rotation axis RA1. The rotation axis RA1 is parallel to the vertical direction. The arm portion 5 pivots horizontally by the rotation of the first joint portion J1. The column part 2 includes a lower part 2-1 and an upper part 2-2. The lower part 2-1 is connected to the fixed part of the first joint part J1. The upper part 2-2 is connected to the rotating part of the first joint part J1, and rotates about the rotation axis RA1. The first and second top rows of the third joint portion J3 serving as a linear motion expansion / contraction mechanism, which will be described later, are housed in the hollow interior of the column portion 2 that forms a cylindrical body. In the upper part 2-2 of the column part 2, a undulating part 4 for accommodating the second joint part J2 as the undulating rotary joint part is installed. The second joint portion J2 is a bending rotation joint. The rotation axis RA2 of the second joint portion J2 is perpendicular to the rotation axis RA1. The second joint portion J2 is placed on the upper portion 2-2 of the column portion 2. The arm portion 5 undulates up and down by the rotation of the second joint portion J2.

The third joint portion J3 is provided by a linear motion expansion / contraction mechanism. Although details will be described later, the linear motion expansion / contraction mechanism has a structure newly developed by the inventors, and is clearly distinguished from a so-called linear motion joint in terms of a movable range. Although the arm portion 5 of the third joint portion J3 is freely bendable, the bending is limited when the arm portion 5 is fed forward along the central axis (extension / contraction center axis RA3) from the base feed mechanism 56 of the arm portion 5, and linear rigidity is thus achieved. Is secured. When the arm part 5 is pulled back, the bending is recovered. The arm unit 5 includes a first frame row 51 and a second frame row 52. The first frame row 51 is composed of a plurality of first frames 53 that are connected to be freely bent. The first frame 53 is formed in a substantially flat plate shape. The second frame row 52 includes a plurality of second frames 54. The second frame 54 forms a groove-like body having a U-shaped cross section. The second frame 54 is connected to be bent by a connecting shaft of the bottom plate. The bending of the second frame row 52 is limited at a position where the end surfaces of the side plates of the second frame 54 come into contact with each other. At that position, the second frame row 52 is linearly arranged. The first first frame 53 in the first frame sequence 51 and the first second frame 54 in the second frame sequence 52 are connected by a combined frame 55. For example, the combined frame 55 has a shape obtained by combining the first frame 53 and the second frame 54.

The first and

second frame rows

51 and 52 are pressed and joined to each other when passing between a plurality of rollers 59 arranged vertically. By joining, the first and

second frame rows

51 and 52 exhibit linear rigidity and constitute a columnar arm portion 5. A drive gear 56 is provided behind the roller 59. The drive gear 56 is connected to a stepping motor via a speed reducer (not shown). A linear gear is formed at the center of the inner surface of the first frame 53 along the connecting direction. When the plurality of first frames 53 are arranged in a straight line, adjacent linear gears are connected in a straight line to form a long linear gear. The drive gear 56 is meshed with the linear gear of the first frame 53 pressed by the guide roller 57. The linear gear connected in a straight line forms a rack and pinion mechanism together with the drive gear 56. When the drive gear 56 rotates forward, the first and

second frame rows

51 and 52 are fed forward from the roller 59. When the drive gear 56 rotates in the reverse direction, the first and

second frame rows

51 and 52 are pulled back to the back of the roller 59. The pulled back first and

second frame rows

51 and 52 are separated between the roller 59 and the drive gear 56. The separated first and

second frame rows

51 and 52 are returned to a bendable state. The first and

second frame rows

51, 52 that have returned to the bendable state are both bent in the same direction (inner side), and are stored vertically in the column portion 2. At this time, the first frame row 51 is stored in a state of being substantially aligned with the second frame row 52 substantially in parallel.

The wrist part 6 is attached to the tip of the arm part 5. The wrist 6 is equipped with fourth to sixth joints J4 to J6. The fourth to sixth joints J4 to J6 are each provided with three orthogonal rotation axes RA4 to RA6. The fourth joint portion J4 is a torsional rotary joint centered on a fourth rotation axis RA4 that substantially coincides with the expansion / contraction center axis RA3, and the end effector is swung and rotated by the rotation of the fourth joint portion J4. The fifth joint portion J5 is a bending rotation joint about the fifth rotation axis RA5 arranged perpendicular to the fourth rotation axis RA4, and the end effector is tilted back and forth by the rotation of the fifth joint portion J5. Is done. The sixth joint portion J6 is a torsional rotational joint about the sixth rotational axis RA6 that is arranged perpendicular to the fourth rotational axis RA4 and the fifth rotational axis RA5. By the rotation of the sixth joint portion J6, The end effector is pivoted.

The end effector (hand effector) is attached to an adapter 7 provided at the lower part of the rotating part of the sixth joint part J6 of the wrist part 6. The end effector is a part having a function of directly acting on a work target (work) by the robot, and various tools such as a gripping part, a vacuum suction part, a nut fastener, a welding gun, and a spray gun exist. The end effector is moved to an arbitrary position by the first, second, and third joint portions J1, J2, and J3, and is disposed in an arbitrary posture by the fourth, fifth, and sixth joint portions J4, J5, and J6. In particular, the length of the expansion / contraction distance of the arm portion 5 of the third joint portion J3 enables the end effector to reach a wide range of objects from the proximity position of the base 1 to the remote position. The third joint portion J3 is a characteristic point that is different from the conventional linear motion joint in the linear expansion / contraction operation realized by the linear motion expansion / contraction mechanism constituting the third joint portion J3 and the length of the expansion / contraction distance.

The first joint portion J1 has a cylindrical or annular rotating pedestal 23. The rotating pedestal 23 is connected to the base 1 of the support column 2. The rotating frame 24 that is rotatably supported on the rotating base 23 has a cylindrical shape or an annular shape. The pulled back first and

second frame rows

51 and 52 are housed in the hollow interior of the rotating frame 24. A rotary shaft of a motor (not shown) is connected to the rotary frame 24 directly or jointly via a power transmission mechanism.

On the rotating frame 24, a pair of side frames 50 as a fixing portion (supporting portion) of the second joint portion J2 is placed. A pair of side frames 50 supports a drum body 60 as a rotating portion that also serves as a motor housing. One end of the drum body 60 is rotatably supported by one side frame 50. A motor unit including a motor and a gear box is fixed inside the drum body 60. An output shaft (drive shaft) of the motor unit is fixed to the other side frame 50. As the output shaft rotates, the drum body 60 rotates about the rotation axis RA2.

A delivery mechanism 56 is attached to the peripheral surface of the drum body 60. As the drum body 60 rotates, the delivery mechanism 56 rotates, and the arm portion 5 supported by the delivery mechanism 56 rises and falls. As shown in FIG. 5, the feed mechanism 56 includes a plurality of upper and lower rollers 59, a plurality of left and right rollers 62, a drive gear 64, and a guide roller 69. This is the main structure of the three joints J3). The number of the upper and lower rollers 59 is eight, for example, four of which are arranged on the upper side and the remaining four are arranged on the lower side. The four rollers 59 on the upper side and the lower side are arranged in a row so that the rotation axes are parallel to each other. The upper four rollers 59 and the lower four rollers 59 are separated by a distance equivalent to the total thickness of the joined first and

second frames

53 and 54. Thereby, the first and

second frames

53 and 54 can be joined, firmly sandwiched from above and below, and supported so as to be movable back and forth. There are six left and right rollers 62, for example, three of which are arranged on the left side and the remaining three on the right side. The three rollers 62 on the left side and the right side are arranged linearly in parallel to each other and in a direction perpendicular to the rotation axis. The three rollers 62 on the left side and the three rollers 62 on the right side are separated by a distance equivalent to the width of the first and

second frames

53 and 54. Thus, the first and

second frames

53 and 54 are firmly sandwiched from the left and right and supported so as to be movable back and forth.

These

rollers

59 and 62 have, for example, polyacetal (POM), polyamide (PA), polytetrafluoroethylene (polyacetal (POM), polyamide (PA), lower durability than aluminum so as not to damage the first and

second frames

53 and 54 made of, for example, aluminum. A cylinder made of a self-lubricating resin such as PTFE (fluorine resin) or an aluminum cylinder whose outer periphery is coated with a self-lubricating resin. Therefore, the service life of the

rollers

59 and 62 is shorter than that of the first and

second frames

53 and 54, and the replacement frequency is relatively high.

A drive gear 64 is disposed with the guide roller 69 behind the

rollers

59 and 62. The guide roller 69 is separated from the drive gear 64 by a distance equivalent to the thickness of the first frame 53. The first frame 53 is pressed against the drive gear 64 by the guide roller 69. The drive gear 64 is meshed with a linear gear formed on the inner surface of the first frame 53. The rotation shaft of the drive gear 64 is connected to a drive shaft of a motor (not shown). The drive gear 64 sends out the first frame 53 forward when the motor rotates forward, and pulls it back backward when the motor rotates backward.

As described above, the

rollers

59 and 62 are relatively replaced more frequently than the first and

second frames

53 and 54. The relative position of the drive gear 64 and the guide roller 69 that sandwich the first frames 53 arranged in a straight line with respect to the

rollers

59 and 62 is required to be accurate. Therefore, in the past, the

rollers

59 and 62, the drive gear 64, and the guide are required. The feeding mechanism 56 equipped with the roller 69 is configured integrally with a single frame. The delivery mechanism 56 is fixed to the peripheral surface of the drum body 60 of the undulating portion 4, and the drum body 60 of the undulating portion 4 is disposed at a place where the internal structure such as the side frame 57 is involved. Further, the drive gear 64 and the guide roller 69 sandwich the first frame 53. Therefore, in order to replace the

rollers

59 and 62, the entire feeding mechanism 56 is removed from the drum body 60 of the undulating portion 4, and the first and

second frame rows

51 and 52 are disassembled and pulled out from the feeding mechanism 56. Was required and the workability was very low.

In the present embodiment, in order to improve the workability, the feed mechanism 56 includes a roller unit 58 equipped with

rollers

59 and 62, and a drive unit 63 equipped with a drive gear 64 and a guide roller 69 as structurally separate bodies. is doing. The drive unit 63 is fixed to the drum body 60 of the undulating portion 4. A roller unit 58 equipped with

rollers

59 and 62 with respect to the drive unit 63 is configured to be detachable. When maintenance such as replacement of the

rollers

59 and 62 becomes necessary, the roller unit 58 is removed from the drive unit 63 while the drive unit 63 is fixed to the drum body 60 of the undulating portion 4. Since the roller unit 58 can be removed while the drive gear 64 of the drive unit 63 and the guide roller 69 sandwich the first frame 53, it is not necessary to disassemble the first and

second frame rows

51 and 52. . By removing the wrist portion 6 from the tip of the arm portion 5, the arm portion 5 is inserted through the

rollers

59 and 62 of the roller unit 58, and the roller unit 58 is separated from the arm portion 5. The damaged

rollers

59 and 62 can be easily replaced by taking out.

As a structure of the roller unit 58, the shaft of the roller 59 is held by screwing from both sides to a pair of opposing side plates 61. Each side plate 61 has a rectangular cutout, and right and left rollers 62 are fitted into the cutout, and the shaft is fixed by screwing. The drive unit 63 is also a pair of side plates 66 and holds the shaft of the guide roller 69 from both sides by screwing, and supports the drive gear 64 below the guide roller 69 with a distance equivalent to the thickness of the first frame 53. . The side plate 66 is configured with the same thickness as the side plate 61. The roller unit 58 and the drive unit 63 are joined in a stepped shape in which the step 67 is alternately meshed at the rear edge of the side plate 61 and the front edge of the side plate 66, and the side plate 61 of the roller unit 58 is connected to the drive unit 63 at the joined portion 68. The side plate 66 is fastened with screws 65 at a plurality of positions, here, at four positions. A step 67 at the rear end of the side plate 61 of the roller unit 58 is formed to ½ of the thickness of the side plate 61, and a step at the front end of the side plate 66 of the drive unit 63 is also formed to ½ of the thickness of the side plate 66. Thus, the thickness of the joint portion 68 is equivalent to the thickness of the side plate 61 of the roller unit 58 and the side plate 66 of the drive unit 63.

The roller unit 58 and the drive unit 63 are joined in a step-like manner, and the joining portion 68 is fastened with a screw 65, so that the roller unit 58 can be firmly joined to the drive unit 63 without rattling. The roller unit 58 can be easily removed from the drive unit 63 by removing the eight screws 65.

The side plate 61 of the roller unit 58 is configured in a tapered shape whose width gradually decreases toward the rear. The rear edge of the side plate 61 of the roller unit 58 is joined to the front edge of the side plate 66 of the drive unit 63 at two sides 71 and 73 that intersect at 135 degrees as an obtuse angle. One joining side 71 is orthogonal to the center line 100 of the region through which the arm portion 5 is defined by the row of the upper rollers 59 and the row of the lower rollers 62. The other joint side 73 is inclined with respect to the center line 100 at an acute angle, for example, 45 degrees.

Since the roller unit 58 is joined to the roller unit 58 at the obtuse two sides 71 and 73, the workability of the positioning especially for mounting the roller unit 58 on the roller unit 58 is improved. The

rollers

59 and 62 can be accurately arranged at a predetermined relative position with respect to the accuracy, that is, the drive gear 64 and the guide roller 69.

As described above, according to the present embodiment, the workability of exchanging the rollers constituting the linear motion expansion / contraction mechanism of the robot arm mechanism is improved.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Base part, 2 ... Arm part, 3 ... Hand effector, J1, J2, J4, J5, J6 ... Rotary joint part, J3 ... Direct acting expansion-contraction joint part (direct acting expansion-contraction mechanism), 53 ... 1st top | frame, 54 ... second frame 56 ... feeding mechanism 58 ...

roller unit

59, 62 ...

roller

61, 66 ... side plate 63 ... drive unit 64 ... drive gear 67 ... step difference 68 ... joining portion 69 ... guide roller

Claims

A support column having a swivel rotary joint is supported on a base, and a undulation having a undulation rotary joint is placed on the support, and the undulation includes a linearly stretchable arm. And a wrist part to which an end effector can be attached is provided at the tip of the arm part, and the wrist part has at least one rotary joint part for changing the posture of the end effector. In the equipped robot arm mechanism,
The linear motion extension mechanism is
A plurality of flat plate-shaped first pieces and the first pieces are connected to each other so that they can be bent at the front and rear ends.
A plurality of second pieces having a groove shape with a U-shaped cross section, and the second pieces are connected to each other so that they can be bent at the front and rear ends of the bottom plate;
A coupling portion that couples the tops of the plurality of first frames and the tops of the plurality of second frames, and the first and second frames are joined to form a straight line when the first and second frames are joined; The first and second frames return to a bent state when separated from each other;
A plurality of rollers for firmly holding the first and second frames and supporting them in a movable manner in order to secure the joined state of the first and second frames, and the separated first frame behind the rollers; A feed mechanism having a drive gear that is engaged with a linear gear of the first gear and that feeds the first frame forward and pulls it backward.
The delivery mechanism is configured separately as a roller unit equipped with the roller and a drive unit equipped with the drive gear, and the drive unit is fixed to the rotating part of the undulation part, and the roller unit The robot arm mechanism is configured to be detachable.
The side plate that constitutes the roller unit and the side plate that constitutes the drive unit are joined in a stepped shape in which the steps are alternately meshed, and the side plate of the roller unit and the side plate of the drive unit are fastened with screws at this joining portion. The robot arm mechanism according to claim 1.
3. The robot arm mechanism according to claim 2, wherein the thickness of the joining portion is equivalent to the thickness of the side plate of the roller unit and the other portion of the side plate of the drive unit.
3. The robot arm mechanism according to claim 2, wherein the side plate of the roller unit is formed in a tapered shape.
3. The robot arm mechanism according to claim 2, wherein the roller unit is joined to the drive unit at two sides intersecting at an obtuse angle.
A plurality of flat plate-shaped first pieces and the first pieces are connected to each other so that they can be bent at the front and rear ends.
A plurality of second pieces having a groove shape with a U-shaped cross section, and the second pieces are connected to each other so that they can be bent at the front and rear ends of the bottom plate;
When the first and second frames are joined to each other, the connecting portion that connects the tops of the plurality of first frames and the tops of the plurality of second frames, and the first and second frames are straightened. Return to a bent state when separated from each other,
A plurality of rollers for firmly holding the first and second frames and supporting them in a movable manner in order to secure the joined state of the first and second frames, and the separated first frame behind the rollers; A feed mechanism having a drive gear that is engaged with a linear gear of the first gear and that feeds the first frame forward and pulls it backward.
The feed-out mechanism is configured separately as a roller unit equipped with the roller and a drive unit equipped with the drive gear, and the roller unit is configured to be detachable from the drive unit. Dynamic expansion and contraction mechanism.